SPL Audio Sweep and test tones

accentsound · 09-01-2005, 01:58 PM

We at Accent Sounds have put up on our website Several Audio Frequency Sweep tones that can be used to test the Subwoofer response of your system Or to be used during SPL competitions when you do your run rather than playing music.

These files are in MP3 format at 192 kb sampling.

Go to

http://www.accentsounds.com/main.htm then click on the web forum button on the left side. Register (Its Free) and there you will find the link to the MP3 Files.

Enjoy.

Accent Sound

Mad Ad · 09-01-2005, 06:14 PM

hmm, well its good that you are trying to give over something to help the community but 192kbps??!! Thats really not high enough quality to be serious use.... blind tests rate 256k the minimum to fool the ear that its cd quality but for audio testing dont forget that mp3 is a lossy format and even 320kbps doesnt have all the aural dynamics of a lossless recording that you really need to test things like low lows (but is better than nothing- I have a set in 320k and its ok but then I dont compete, its just for my personal use, setting x-o levels on my FRX456).

If you are actually manufacturing the tones yourself, perhaps consider releasing a set in .wav format - i mean sine sweeps arent going to be that large a file, even in .wav but if you make seperate links so people can choose individual tracks or take the package itll make your site more desirable to visit

as well as give you more credibility among the real SPL/SQL heads.

(note if you are not making your own tones, expanding the 192k mp3s will not increase the quality)

OzOnE · 09-01-2005, 11:50 PM

Hi,

This is my second post since joining today (or yesterday, I can't remember), so be gentle.

This has probably been talked about before, but I didn't find too much when doing a quick search so hopefully this might help someone...

I've been using some handy software for a while now to help set up my home cinema speakers...

You should just as easily be able use this kind of software on a Carputer (or laptop) for fine-tuning your car's audio performance. I'm sure a program like Room EQ Wizard could be used in a car...

http://homepage.ntlworld.com/john.mu...meq/index.html

You will need a decent microphone or a SPL meter for this though. If you don't have a good microphone, the measurements won't be accurate, and your car audio will probably end up sounding worse than ever.

So called "Measurement Microphones" are usually very expensive for what they are, and you can build a very simple, but very good mic by just buying a cheap Panasonic type electret mic capsule like the ones seen at the following site...

http://www.vikash.info/audio/measurement_mic/

You can then use the software on your Carputer to get an accurate flat frequency response from your speakers and also get a smoother crossover between the main speakers and your sub(s).

I also use Realtime Analyser a lot for adjusting the time delays on my 7.1 speaker setup at home....

http://www.ymec.com/products/dssf3e/outline.htm

You just use the Impulse Response function of the software and any old microphone (don't really need a decent mic for IR) to match all the time delays of each speaker as closely as you can by adjusting the delays on your amp / car PC.

The only problem is getting the signal to only one channel (speaker) at a time when you're testing it, and I'm not sure how you would do this with a Carputer setup yet.

I think that matching the speaker delays is only really handy for when you're listening to DVD or DivX movies in the car which have Dolby Digital / DTS soundtracks. It definitely makes a noticable difference in a home cinema though, and it's one of the simplest ways of accurately setting the speaker delays that I know of.

(I suppose it could improve music quality too though if you're balancing more than one pair of stereo speakers.)

Right, I think I'd better go to sleep soon as it's 5:30am here now! I've been spending FAR too much time reading up on this Carputer stuff, especially seeing that I don't even have a car and I'm doing a Carputer install for a friend.

I guess I must be more excited about it than he is. Opus 150 on it's way!

OzOnE

Oh, almost forgot. The Room EQ Wizard outputs values for adjusting a BFD Pro, which is just a fancy graphic EQ. You can still use the output values with any decent graphic EQ hardware or software.

Mad Ad · 09-02-2005, 05:57 PM

very interesting, looks fiddly but im sure its worthwhile if you persevere with it